| Applies To | |
| Product(s): | AutoPIPE Vessel |
| Environment: | N/A |
| Area: | Calculations |
| Original Author: | Bentley Technical Support Group |
| Date Logged & Current Version |
Oct. 2024 45.00.02.004 |
Problem:
Where to input extra cladding thickness on tubesheets?
Example 1:
input 3.2 mm of cladding on shell and tubes side. But we want to increase cladding on tubesheet until 9.5 in shell side and 8 on tube side. How can I do this? Should I input those values in corrosion field? (if I do that hfl is bigger than hp on floating tubesheet).
Solution:
The clad can be taken into account as a corrosion allowance, but this is just a workaround (there is an enhancement in the backlog: TFS#72825).
hfl is bigger than hp in the model because the corrosion (tube side) is not applied on hfl (thickness of the flanged extension), see below the detail of the calculation:
thickness of the flanged extension : hfl
thickness at the periphery : hp
thickness of the tubesheet: hnew = 329 mm
Corrosion Shell Side: CAss = 9.5 mm
Corrosion Tube Side: CAts = 8 mm
Extra thickness (machining extension): hg = 8 mm
Extra thickness (recessed face): hf = 5 mm
hfl = hnew - hg - hf - CAss = 329 -8-5-9.5 = 306.5 mm
hp = hnew - hg - CAts - CAss = 329 -8-8-9.5 = 303.5 mm
Example 2:
Where I should input cladding on Tubesheet if I need 5 mm minimum of cladding on Tubesheet tubeside face? But also 3 mm cladding should be on Tubesheet gasket face.
Solution:
The only option to add the cladding on the Tubesheet is adding corrosion allowance. Again, you can only consider the corrosion allowance on surface which comes in contact with fluid.
AutoPIPE Vessel does not add corrosion allowance on gasket facing surfaces.
See the below input window from AutoPIPE Vessel.
See below the detail of the calculation:
Thickness of the tubesheet: hnew = 196 mm
Corrosion Shell Side: CAss = 3 mm
Corrosion Tube Side: CAts = 6.5 mm
Extra thickness (machining extension): hg = 5 mm
Extra thickness (recessed face): hf = 5 mm
Tolerances: tol = 1.6 mm
h (corroded) = hnew - CAss - CAts - tol = 196-3-6.5-1.6 = 184.9 mm
hp (corroded) = h (corroded) - hg - hf = 184.9 -5-5 = 174.9 mm
See below AutoPIPE Vessel report snap for your reference.